One way of re-sealably closing such cans is known from pages 2746-2747 of the Amtsblatt des Kantons Graubünden, published on 13 Sep. 1996. This publication describes a resealable closure which comprises a lid for permanently fixing to a can body, and a removable sealing device for sealing a pouring aperture in a panel of the lid. The sealing device comprises two parts (called “leaves”), which are joined by an integral hinge. The sealing component is connected to a can end panel by a further hinge, the can end and sealing device together forming the closure.
Although, in theory this closure is re-sealable, in practice sealing is extremely difficult to achieve due to the interference or push fit between the various parts of the sealing component. Further problems with this closure are that there is no clear device for indicating tampering, the sealing device requires a specially formed can end panel, and there is a risk of “missiling” of the sealing component due to the inadequate way with which it is fixed to the rest of the closure.
Another way of re-sealably closing a beverage can is known from U.S. Pat. No. 4,369,888. This patent describes a one-piece closure with two integral hinges. However, although opening of the closure is aided by the ability to lever one part relative to another, it is extremely difficult to re-seal the closure again due to the interference fit between the various parts. In addition, the closure can get in the way of the aperture when a consumer attempts to drink from the can.
Since this type of re-sealable closure typically uses sealing components which are made from plastic materials, it is preferable to be able to remove the closure/sealing components completely before re-cycling the metal can. However, this requirement may cause problems since if the sealing device is relatively simple to remove from the can then there is a risk of missiling before the closure has been opened and vice-versa.